A so-called guide groove type has conventionally been well-known as this type of welding gun, as disclosed in, for example, Patent Document 1, in which a movable gun arm is moved (opened or closed) by sliding and guiding part of the arm side, by way of a guide groove formed in the gun body side. According to the disclosure, a pin or roller follower is provided to part of the arm side, and is engaged with the guide groove, thereby facilitating the operation of opening or closing the movable gun arm.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2012-35274